224 THOMAS SAY FOUNDATION 



bent hairs or small bristles. It extends far forward 

 under the abdomen, the anus near the extreme front 

 end, and from this back to the second segment it has 

 a distinct median groove which has susre^ested the spe- 

 cific name. Forceps minute, yellow, the free part 

 slender, bent back and convergent at apex, with more 

 or less of a knob on the outer side. As the forceps 

 are divergent near the base, they enclose an oval open- 

 ing when viewed from behind. Accessory plate yel- 

 low, lar^e, concave, rather oval or quadrangular, so 

 large that they conceal most of the inner organs, and 

 in making the drawing it was necessary to remove 

 the plate and indicate its position by a dotted line. 

 Posterior clasper yellow, very wide in profile, the 

 apex developed into two divergent points connected 

 by a membrane ; anterior claspers yellow, exceedingly 

 slender and delicate toward the tip, rather upright in 

 position. Penis with a very slender, yellow basal por- 

 tion, the distal part yellowish, developed backward 

 from the basal segment more than usual, with a black 

 spot on the side; without any visible processes or 

 plates except on the front side near the tip, where 

 there is a minute double row of recurved and appar- 

 ently branched spines. Fifth sternite very widely ex- 

 cised, the only part showing being rounded yellow 

 lobes on each side, tipped with black and clothed with 

 long hairs. 



Legs black ; middle femur without comb ; middle 

 tibia with two long bristles on outer front side; hind 

 femur with well developed but rather short villosity. 



Wings hyaline; no costal spine; third segment of 

 costa equaling the fifth. First vein bare ; third hairy 

 nearly to crossvein. 



Female. Front .370 of head ; sides parallel nearly 

 to antenna, with usual orbital bristles. Back of head 

 as in male, but pale beard showing rather more dis- 

 tinctly; third segment of abdomen with well devel- 

 oped median marginal bristles and enough lateral 

 ones to form an interrupted row ; fourth segment red- 

 dish at tip. Genital segment red with roundish open- 



